Jolted into action by a wave of hate crimes that followed the election victory of Donald J. Trump, American Muslims and Jews are banding together in a surprising new alliance.
They are putting aside for now their divisions over Israel to join forces to resist whatever may come next. New groups are forming, and interfaith coalitions that already existed say interest is increasing.

Vaseem Firdaus, a Muslim who has lived in the United States for 42 years, spent Friday night at a Shabbat dinner for members of a women’s group called the Sisterhood of Salaam Shalom, in a home here filled with Jewish art and ritual objects.

Until Mr. Trump was elected president, Ms. Firdaus, who is 56 and a manufacturing manager at Exxon Mobil, felt secure living as a Muslim in America. She has a daughter who is a doctor and a son who is an engineer, and she recently traveled to Tampa with her husband looking to buy a vacation home. But Mr. Trump’s victory has shaken her sense of comfort and security.

After joining in blessings over home-baked challah and sparkling grape juice (instead of wine, out of consideration for the Muslims), Ms. Firdaus talked with four Jewish women she had never met before, balancing plates of Indian food on their laps.

They found that the spate of hate crimes and the ominous talk by Mr. Trump or his advisers about barring Muslims from entering the country and registering those living here had caused all of them to think about Germany in the years before the Holocaust.

“When did you know it was time to leave?” Ms. Firdaus asked one woman who had just recounted how her relatives had fled the Nazis. “The ones that didn’t leave are the ones who went to Auschwitz.”

The Jewish women tried to convince her that they would not let it come to that. “If Muslims have to register, we’re all going to register,” said Mahela Morrow-Jones, who is helping to build the first West Coast chapter of the Sisterhood in Santa Barbara, Calif. “You’ve got to believe it, sister.”

Groups are reaching out not just to clergy members, but also to laypeople, including business executives, students and women.
Conference participants discussing how to prevent “extremist narratives.”

Jonathan Greenblatt, the chief executive of the Anti-Defamation League, said in a recent interview: “Jews know what it means to be identified and tagged, to be registered and pulled aside. It evokes very deep emotions in the Jewish community.”

Mr. Greenblatt received a standing ovation when he declared at his organization’s conference in Manhattan last month that if Muslims were ever forced to register, “that is the day that this proud Jew will register as a Muslim.”

“All of us have heard the story of the Danish king who said if his country’s Jews had to wear a gold star,” he said, “all of Denmark would, too.”

Nearly 500 Muslim and Jewish women, many wearing head scarves and skullcaps, gathered on Sunday at Drew University in Madison, N.J., in what organizers said was the largest such meeting ever held in the United States. It was the third annual conference of the Sisterhood of Salaam Shalom, a grass-roots group that now claims 50 chapters in more than 20 states. The first conference two years ago drew only 100 people.

The women spread out inside an enormous sports complex and met in clusters to study sacred texts on the racquetball courts, practice self-defense techniques in the dance studio and, in the bleachers, discuss how to talk to friends whose impression of Islam had been shaped entirely by news of terrorist attacks.

Over lunch and in the hallways, they traded stories about the latest ugly outbreaks back home: a brick thrown through the window of a Muslim-owned restaurant in Kansas, apartments of Muslim families in Virginia hit with eggs and graffiti, swastikas scrawled on synagogues and in a playground in New York. Sisterhood chapters keep track of the incidents on their Facebook pages and other social media.

“Ignorance is one of the key triggers of hate,” said Sheryl Olitzky, the group’s executive director, in her opening remarks. “We need to show the world that we are Americans. We are here because we love each other and we’re overcoming hate.”

Ms. Olitzky, a marketing executive whose husband and two sons are rabbis, started the first Sisterhood women’s meeting in New Jersey six years ago on the theory that “women navigate the world through relationships.”

She baked the challah and hosted the Shabbat dinner on Friday night at her home. The Sisterhood is one of several groups expanding their work on Muslim-Jewish relations: The Foundation for Ethnic Understanding started an initiative to elevate Muslim condemnations of terrorism, which are often ignored by the news media. The Anti-Defamation League is increasing its work against anti-Muslim bigotry.

“It’s the Trump effect,” said Imam Abdullah Antepli, the chief representative on Muslim affairs at Duke University, who attended the women’s conference with his wife. “I see the Muslim community even more eager to reach out and to put aside the grievances of the past.”

The most prominent new initiative is a Muslim-Jewish Advisory Council whose co-chairmen are Fortune 500 chief executives: Farooq Kathwari, of the furniture company Ethan Allen, who is Muslim, and Stanley Bergman, of the medical products distributor Henry Schein, who is Jewish.

The council, which was forming as Mr. Trump’s campaign was gaining steam, includes both Democrats and Republicans. It was created by leaders of the American Jewish Committee and the Islamic Society of North America in an effort to have influence on public policy. The group intends to oppose a registry, support immigrants and refugees, and push for accommodating religious practices in the workplace.